Question

If the length and breadth of a rectangle are doubled then its perimeter is 

(1) tripled (2) doubled (3) made half (4) None of these

Answer 1

(2) Let the initial length and breadth be l and b, respectively.

So, the initial perimeter = 2 (l + b)

The final perimeter = 2 (2l + 2b) = 4 (l + b)

Now, Final perimeter/Initial perimeter = 4(l + b)/ 2( + b)= 2